Cyanuric acid is a compound that historically has been used as a chlorine stabilizer in swimming pool water. Although widely accepted in the recreational water industry for this use, cyanuric acid has the drawback of being relatively insoluble in water (0.25% at 75° F.) and acidic (pH 2.8 to 4.5). Because acidic chemicals in pool water will cause metal corrosion as well as damage to certain types of pool tile and vinyl liners, the addition of alkaline compounds is required to adjust pool water to an ideal range of pH 7.4 to 7.6.
Monosodium cyanurate has an alkaline pH and is considerably more soluble in water than cyanuric acid and consequently has been of interest to the pool industry. A number of complex approaches exist to produce monosodium cyanurate. Slurry products are described in U.S. Pat. No. 6,207,177 issued to Jany and in U.S. Pat. No. 4,233,444 issued to Doonan et al., wherein alkali metal hydroxides are reacted with cyanuric acid in solution. These methods have the disadvantage of involving considerable quantities of water, generally 60% to 80% by weight, and require expensive filtration and drying equipment as well as sizing machinery to achieve a suitable dry product.
Shimamura et al., in U.S. Pat. No. 4,432,959, disclose a complex method for making sodium cyanurate involving reacting iso cyanuric acid with sodium carbonate or sodium hydrogencarbonate and heating the composition to temperatures between 70 to 100° C.
It would be advantageous and thus there is a need for a less complex procedure to produce an alkali metal cyanurate that does not require heating, uses little water and is produced as a powder.